This invention relates generally to plant growing media, and, more particularly, to growing media particularly suitable for use in growing sod.
Grass lawns are now commonly produced by growing sod at special sod farms and then harvesting the sod and shipping it via truck to an installation site. There, the sod is laid out on specially-prepared ground, where the grass roots from the sod can grow into the ground to form a secure grass lawn. The sod is typically grown at the sod farm in a medium of soil, with a predetermined soil depth being removed with each harvest. Plastic sheeting is sometimes used to form a barrier that limits the depth of root growth.
A large proportion of the total cost of the sod is attributable to the cost of trucking it to the installation site. This is due in large part to the sod's extremely heavy weight, which sharply limits the amount that can be transported on each truck. It is therefore desirable to utilize a growing medium that is significantly lighter in weight than conventional soil.
There have been several prior attempts to grow sod using lightweight growing compositions as alternatives to soil. The compositions are used by spreading them onto a plastic sheet, which confines root growth to the composition and not the underlying ground. None of these prior attempts is believed to have been entirely successful. The lightweight compositions used in the past are not believed to carry as much water as is possible to carry and are not believed to be as light in weight as is possible. In addition, some lightweight media used in the past have sometimes included components (e.g., crushed conifer bark) that are not readily available in many regions.
It should therefore be appreciated that there is a need for a germinating and growing medium for grass that comprises readily available materials, is convenient to use, and is capable of holding vast quantities of water, yet when dry is light in weight to facilitate its economic transport. The present invention fulfills this need.